1. Field of the Invention
The present invention relates to a display device and particularly to a technology that is effective for a random number generating circuit that is used in a display device.
2. Description of the Related Art
Thin film transistor (TFT) liquid crystal display devices that include medium-sized liquid crystal display panels are widely used as display portions in portable terminals and laptop personal computers.
Among these medium-sized liquid crystal display devices, there are devices that are also disposed with a touch panel as an input device for data that are inputted from the outside. Further, keyboards that have conventionally been used are also used as external input devices.
There are cases where, in order to maintain confidentiality, coding such as encryption is administered to data that have been inputted from these input devices. Random numbers are usually used for the coding, and a need has arisen for display devices to also be equipped with a random number generating circuit.
However, conventional display devices are not equipped with a random number generating circuit, and random number generating devices that are optimum for general-purpose display devices are being tried.
Meanwhile, various random number generating circuits have conventionally been proposed, and in JP-A-06-051957, there is description of a circuit that generates random numbers called M-sequences in shift registers. However, in JP-A-06-051957, there is no description in regard to a random number generating circuit that is used in a display device.